com.ocpsoft.pretty.config.PrettyConfigurator Maven / Gradle / Ivy
/*
* Copyright 2010 Lincoln Baxter, III
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.ocpsoft.pretty.config;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.StringTokenizer;
import javax.servlet.ServletContext;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.xml.sax.SAXException;
import com.ocpsoft.pretty.PrettyFilter;
/**
* Implements the Pretty Faces configuration procedure.
*
* At application startup time, before any requests are processed, Pretty Faces
* processes zero or more configuration resources, located according to the
* following algorithm:
*
*
* - Search for classpath resources named
*
META-INF/pretty-config.xml in the ServletContext resource paths
* for this web application, and load each as a configuration resource.
* - Check for the existence of a context initialization parameter named
*
com.ocpsoft.pretty.CONFIG_FILES. If it exists, treat it as a
* comma-delimited list of context relative resource paths (starting with a
* /), and load each of the specfied resources.
* - Check for the existence of a web application configuration resource named
*
/WEB-INF/pretty-config.xml, and load it if the resource exists.
*
*
* @author Aleksei Valikov
*/
public class PrettyConfigurator
{
private static final Log log = LogFactory.getLog(PrettyConfigurator.class);
/**
* Name of the classpath configuration resource for Pretty Faces.
*/
public static final String PRETTY_CONFIG_RESOURCE = "META-INF/pretty-config.xml";
/**
* Default path of the Pretty Faces configuration.
*/
public static final String DEFAULT_PRETTY_FACES_CONFIG = "/WEB-INF/pretty-config.xml";
private final ServletContext servletContext;
private final PrettyConfigParser configParser;
/**
* Constructs a new configurator.
*
* @param servletContext
* servlet context, must not be null.
*/
public PrettyConfigurator(final ServletContext servletContext)
{
if (servletContext == null)
{
throw new IllegalArgumentException("Servlet context must not be null.");
}
this.servletContext = servletContext;
configParser = new DigesterPrettyConfigParser();
}
/**
* Loads the Pretty Faces configuration and returns the configuration
* object.
*
* @return Loaded configuration.
* @throws IOException
* If configuration could not be read.
* @throws SAXException
* If configuraion could not be parsed.
*/
public PrettyConfig configure() throws IOException, SAXException
{
final PrettyConfigBuilder builder = new PrettyConfigBuilder();
// Load configurations from the class path
feedClassLoaderConfigs(builder);
// Load configurations from the config files configured in the servlet
// context
feedContextSpecifiedConfig(builder);
// Load configuration from the default path
feedWebAppConfig(builder);
return builder.build();
}
private void feedClassLoaderConfigs(final PrettyConfigBuilder builder) throws IOException, SAXException
{
final Enumeration urls = getResourceLoader().getResources(PRETTY_CONFIG_RESOURCE);
if (urls != null)
{
while (urls.hasMoreElements())
{
final URL url = urls.nextElement();
if (url != null)
{
InputStream is = null;
try
{
is = openStream(url);
configParser.parse(builder, is);
}
finally
{
if (is != null)
{
try
{
is.close();
}
catch (IOException ignored)
{
}
}
}
}
}
}
}
private void feedContextSpecifiedConfig(final PrettyConfigBuilder builder) throws IOException, SAXException
{
final List configFilesList = getConfigFilesList();
for (final String systemId : configFilesList)
{
final InputStream is = servletContext.getResourceAsStream(systemId);
if (is == null)
{
log.error("Pretty Faces config resource [" + systemId + "] not found.");
continue;
}
if (log.isInfoEnabled())
{
log.info("Reading config [" + systemId + "].");
}
try
{
configParser.parse(builder, is);
}
finally
{
try
{
is.close();
}
catch (IOException ignored)
{
}
}
}
}
private List getConfigFilesList()
{
final String configFiles = servletContext.getInitParameter(PrettyFilter.CONFIG_FILES_ATTR);
final List configFilesList = new ArrayList();
if (configFiles != null)
{
final StringTokenizer st = new StringTokenizer(configFiles, ",", false);
while (st.hasMoreTokens())
{
final String systemId = st.nextToken().trim();
if (DEFAULT_PRETTY_FACES_CONFIG.equals(systemId))
{
if (log.isWarnEnabled())
{
log.warn("The file [" + DEFAULT_PRETTY_FACES_CONFIG + "] has been specified in the ["
+ PrettyFilter.CONFIG_FILES_ATTR + "] context parameter of "
+ "the deployment descriptor. This will automatically be removed, "
+ "if we wouldn't do this, it would be loaded twice.");
}
}
else
{
configFilesList.add(systemId);
}
}
}
return configFilesList;
}
private void feedWebAppConfig(final PrettyConfigBuilder builder) throws IOException, SAXException
{
final InputStream is = servletContext.getResourceAsStream(DEFAULT_PRETTY_FACES_CONFIG);
if (is != null)
{
if (log.isInfoEnabled())
{
log.info("Reading config [" + DEFAULT_PRETTY_FACES_CONFIG + "].");
}
try
{
configParser.parse(builder, is);
}
finally
{
try
{
is.close();
}
catch (IOException ignored)
{
}
}
}
}
/**
* Return class loader to be used to resolve resources.
*
* @return Class loader to be used to resolve resources
*/
protected ClassLoader getResourceLoader()
{
final ClassLoader resourceLoader = Thread.currentThread().getContextClassLoader();
return resourceLoader;
}
/**
* Opens an input stream for the given URL.
*
* @param url
* target URL.
* @return Opened input stream.
* @throws IOException
* If connection could not be opened.
*/
protected InputStream openStream(final URL url) throws IOException
{
final URLConnection connection = url.openConnection();
connection.setUseCaches(false);
return connection.getInputStream();
}
}
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